A millimeter wave dual-frequency dual-polarization laminated patch antenna array

Abstract

A millimeter-wave dual-frequency dual-polarization laminated patch antenna array, the antenna array is formed by a plurality of millimeter-wave dual-frequency dual-polarization laminated patch antenna units of the same structure arranged at equal intervals on the surface of a metal floor. The antenna unit includes a low-frequency annular metal patch, a high-frequency butterfly-shaped metal patch, a metal floor, an upper and lower dielectric substrate, and two feeding structures. The annular metal patch is located on the upper surface of the upper substrate, and is used to generate low-frequency resonance; the butterfly-shaped metal patch is located on the upper surface of the lower substrate, and is used to generate high-frequency resonance; the lower substrate is placed on the metal floor. The two feeding structures penetrate the metal floor and the two layers of dielectric substrates respectively. After installation, the two feeding units are coaxial with the preset through holes in each layer, and do not contact the inner wall of the through hole. The two layers of metal patches provided by the present invention are both fed by capacitive coupling. Capacitive coupling feeding can offset the additional inductance introduced by orthogonal coaxial feeding, and can achieve dual-frequency and dual-polarization operation.

Description

Technical Field

[0001] The present invention belongs to the field of 5G wireless communication and antenna technology, and relates to a dual-frequency dual-polarization millimeter wave communication laminated patch antenna array. Background Art

[0002] In recent years, with the rapid development of cellular network technology, its data flow has increased exponentially. Millimeter wave communication technology has been gradually applied to smartphone terminals due to its large bandwidth, high speed and low latency. Currently, the main authorized 5G millimeter wave bands in the world are n257 (26.5-29.5 GHz), n258 (24.25-27.5 GHz), n260 (37.0-40.0 GHz) and n261 (27.5-28.35 GHz). As the functions supported by smartphones become more and more complex, the number of their antennas is also increasing, and the space provided for millimeter waves is very limited. The metal frame of the mobile phone also brings many challenges to the design of the antenna.

[0003] For millimeter waves, the antenna needs to have a high gain due to the large loss of the propagation link. At the same time, the terminal antenna also needs a wide coverage range. The balance between high gain and wide scanning angle brings challenges to antenna design. In addition, due to the limitation of line-of-sight transmission (LOS), millimeter wave communication is prone to polarization mismatch, so dual-polarization characteristics are particularly important for millimeter wave antennas. How to design a small, high-gain, wide-angle scanning, dual-polarization, and high-efficiency millimeter wave mobile phone antenna is of great significance.

[0004] The present invention realizes a millimeter wave dual-frequency dual-polarization antenna unit by designing two layers of radiation patches and feeding through capacitive coupling, thereby achieving high isolation between ports. The two resonance points of low frequency and high frequency can be achieved by adjusting the size of the upper and lower metal patches respectively. The 1×4 linear array designed with the antenna unit realizes a wide angle scanning of ±45°. Summary of the invention

[0005] In order to solve the problem that the millimeter wave terminal antenna is difficult to be miniaturized, has a large bandwidth, high gain, and a wide scanning angle, the present invention designs a millimeter wave antenna array for mobile device terminals. Through the capacitive coupling fed laminated patch antenna, dual-band and dual-polarization are realized to ensure the isolation between orthogonal polarization antennas. And the 1×4 linear array composed of this antenna unit realizes a wide array scanning angle.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A millimeter wave dual-frequency dual-polarization laminated patch antenna array for a mobile terminal, the antenna array is formed by equidistantly arranging a plurality of millimeter wave dual-frequency dual-polarization laminated patch antenna units of the same structure on the surface of a metal floor 3. The millimeter wave dual-frequency dual-polarization laminated patch antenna unit mainly includes a low-frequency annular metal patch 1, a high-frequency butterfly-shaped metal patch 2, a metal floor 3, an upper dielectric substrate 4, a lower dielectric substrate 5 and a feeding structure, wherein the feeding structure includes a +45 degree feeding unit 6 and a -45 degree feeding unit 7.

[0008] The annular metal patch 1 is located on the upper surface of the upper dielectric substrate 4, and the butterfly metal patch 2 is located on the upper surface of the lower dielectric substrate 5, and the lower dielectric substrate 5 is placed on the metal floor 3. In order to prevent the upper metal patch 1 from blocking the normal radiation of the lower high-frequency butterfly metal patch 2, the annular metal patch 1 is a square ring structure; the butterfly metal patch 2 is obtained by chamfering the four right angles of the rectangular patch, and this type of structure can achieve a larger working bandwidth. The four end corners of the butterfly metal patch 2 correspond to the center positions of the four sides of the square ring structure, and the center points of the upper annular metal patch 1 and the lower butterfly metal patch 2 can coincide. The annular metal patch 1 is used to generate low-frequency resonance, and the operating frequency can be adjusted by adjusting the size of the patch 1; the metal patch 2 is used to generate high-frequency resonance, and the high-frequency working frequency can be adjusted by adjusting the size of its rectangular patch and chamfer.

[0009] Two through holes are provided at corresponding positions on the metal floor 3, dielectric substrate 4, and dielectric substrate 5, respectively, for passing through the +45-degree feed unit 6 and -45-degree feed unit 7, wherein the diameters of the through holes are respectively larger than the outer diameters of the +45-degree feed unit 6 and -45-degree feed unit 7; the two feeding probes 6 and 7 are respectively located at the center positions of the two vertically adjacent sides of the square ring structure of the metal patch 1 to excite antennas of different polarizations. After installation, the two feeding units are coaxial with the through holes, and the distance between the feeding units and the inner wall of the through holes is 0~0.1 mm. Both layers of metal patches 1 and 2 are fed by capacitive coupling, and capacitive coupling feeding can offset the additional inductance introduced by orthogonal coaxial feeding. To achieve capacitive coupling feeding, metal patches 1 and 2 are not in direct contact with the two feeding probes 6 and 7. A circle with a radius larger than the radius of the feeding probe can be dug out at the center of the feeding probes of metal patches 1 and 2. By adjusting the radius of the dug circle, the capacitance value can be changed to improve the matching of the antenna. The radius of the dug circle of the upper patch 1 is 0.18~0.2 mm, and the radius of the dug circle of the lower patch is 0.2~0.25 mm. The feeding probe runs through all metal and dielectric layers to achieve common feeding of high and low frequencies. The radius of the feeding probe is 0.15 mm.

[0010] Furthermore, the relative dielectric constants of the two dielectric substrates 4 and 5 affect the working frequency of the antenna and can be adjusted according to frequency requirements.

[0011] Furthermore, in the antenna array, each antenna unit is arranged in the same direction, and the distance between the center points of adjacent antenna units is L 4=4 mm.

[0012] The application of the present invention is: to improve the antenna gain, N dual-frequency dual-polarization laminated patch antenna units are combined into a group of 1×N antenna linear arrays, wherein the N laminated patch antenna arrays are arranged in the same manner, and the center distance between the antenna units is L 4=4 mm, e.g. Figure 3 As shown. The phased array achieves a larger high gain and wide angle scanning. The antenna array finally designed has the advantages of small size, compact structure, wide dual-polarization bandwidth and large scanning angle.

[0013] The working process of the present invention is as follows: external coaxial feeding probes 6 and 7 perform capacitive feeding on metal patches 1 and 2, and the RF signal enters patches 1 and 2 through capacitive coupling. The resonant frequency of patch 1 is approximately millimeter wave low frequency, and the surface current is distributed on both sides of the metal ring of the feeding port. The resonant frequency of patch 2 is millimeter wave high frequency, and the surface current is distributed on the rounded edge of the patch and moves periodically. Due to the orthogonal polarization, the isolation between the antennas is good, higher than 10 dB.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] (1) The millimeter wave antenna unit for a 5G mobile terminal described in the present invention uses two laminated structures of metal patch 1 and metal patch 2 to achieve dual-frequency and dual-polarization operation. The two antennas are excited by the same feed, and the antenna structure is compact, small in size, and low in profile, and is suitable for use in the frame of a mobile phone such as a Qualcomm chip.

[0016] (2) The antenna array can achieve stable directivity patterns in a dual-frequency and wide-band range, achieving a win-win situation of dual polarization, wide scanning angle and small size. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a front schematic diagram of the dual-frequency dual-polarization laminated patch antenna unit proposed by the present invention;

[0018] Figure 2 It is a side view of the dual-frequency dual-polarization laminated patch antenna unit proposed by the present invention;

[0019] Figure 3 It is a schematic diagram of the structure of a dual-frequency dual-polarization laminated patch 1×4 antenna array used in the present invention;

[0020] Figure 4 is the S parameter of the dual-frequency dual-polarization laminated patch antenna unit proposed by the present invention;

[0021] FIG5 is a two-dimensional radiation pattern of the dual-frequency dual-polarization laminated patch antenna unit proposed in the present invention; FIG5(a) is a radiation pattern of the dual-frequency dual-polarization laminated patch antenna unit proposed in the present invention at the E-plane and the H-plane at 29 GHz; FIG5(b) is a radiation pattern of the dual-frequency dual-polarization laminated patch antenna unit proposed in the present invention at the E-plane and the H-plane at 39 GHz;

[0022] Figure 6 These are some of the S parameters used in the dual-frequency dual-polarization laminated patch 1×4 antenna array of the present invention;

[0023] FIG7 (a) to (c) are beam scanning angles of the dual-frequency dual-polarization laminated patch 1×4 antenna array at 29 GHz, 39 GHz and 43.5 GHz in the present invention;

[0024] In the figure: 1 annular metal patch, 2 butterfly-shaped metal patch, 3 metal floor, 4 upper dielectric substrate, 5 lower dielectric substrate, 6 +45 degree feed unit, 7 -45 degree feed unit. DETAILED DESCRIPTION

[0025] The specific implementation scheme of the present invention is described in detail below in conjunction with the accompanying drawings and technical solutions of the specification.

[0026] See also Figure 1 , Figure 2 The dual-frequency dual-polarization laminated patch antenna unit is composed of four parts: two layers of dielectric substrates, a metal floor, two antenna radiation patch units and a feeding structure, wherein the antenna radiation unit includes a metal ring patch 1 and a metal patch 2. The ring metal patch 1 is placed on the upper surface of the upper dielectric substrate 4, and the butterfly metal patch 2 is located on the upper surface of the lower dielectric substrate 5, and the lower layer of the lower dielectric substrate 5 is a metal floor 3. The ±45 dual-polarization characteristics of the antenna are achieved by using an orthogonal coaxial feeding method. The ring metal patch 1 and the butterfly metal patch 2 work in the low-frequency and high-frequency bands of the millimeter wave respectively, and the antenna resonance point can be adjusted by adjusting the patch size. On the two layers of patches, a circle with a radius slightly larger than the probe radius is cut off at the center of the probe to achieve capacitive coupling feeding to offset the additional inductance introduced by the orthogonal coaxial feeding.

[0027] The overall size of the dual-frequency dual-polarization laminated patch antenna unit is about 4×4×1.1 mm³. The outer length of the metal patch 1 L 1 is 1.9 mm, the length of the cut rectangular patch L 2 is 1.425 mm. The outer length of the metal patch 2 L 3 is 1.85mm, the radius of the chamfer at the four right anglesR 1 is 0.73 mm. In order to realize the coaxial capacitive feeding mode, a circle with a radius of 0.2 mm is dug out at the center of the probe circle of the upper patch, and a circle with a radius of 0.22 mm is dug out at the center of the probe circle of the lower patch. The material used for dielectric substrate 4 is F4BTME-1 / 2, with a relative dielectric constant of 3.5, a loss tangent of 0.002, and a thickness of 0.254 mm. The material used for dielectric substrate 5 is Rogers RO4730G3, with a relative dielectric constant of 2.98, a loss tangent of 0.003, and a thickness of 0.78 mm.

[0028] The dual-frequency dual-polarization millimeter wave antenna unit is fed through a coaxial connector, and the obtained S parameters are as follows: Figure 4 As shown in the figure, it can be seen that the antenna unit generates resonance points at 28 GHz in the low frequency band and 39 GHz in the high frequency band, the -10 dB operating frequency band ranges from 26.3 to 29.7 GHz and 36.5 to 44.5 GHz, the isolation in the low frequency band is greater than 13 dB, and the isolation in the high frequency band is greater than 14 dB, achieving wideband characteristics in the high frequency band.

[0029] Figure 5(a)~(b) are the radiation patterns of the E-plane and H-plane of the dual-frequency dual-polarization laminated patch antenna unit proposed in the present invention at 29 GHz and 39 GHz. It can be seen that the radiation of the antenna unit is all zenith radiation, and the gain is greater than 5 dB.

[0030] Figure 3 The figure is a schematic diagram of the structure of the dual-frequency dual-polarization laminated patch antenna array of the present invention (the upper dielectric layer is hidden). The array is composed of the aforementioned antenna units arranged in 1×4, and the overall size of the array is 16×4×1.1 mm³. In order to improve the antenna gain, the four dual-frequency dual-polarization laminated patch antenna units are combined into a 1×4 antenna linear array, where the N laminated patch antenna arrays are arranged in the same manner, and the distance between the antennas is L 4=4 mm, e.g. Figure 3 As shown. A phased array is used to achieve higher gain and wide-angle scanning. The antenna array finally designed has the advantages of small size, compact structure, wide dual-polarization bandwidth, and large scanning angle.

[0031] Figure 6 The present invention proposes Figure 3 The S-parameter results of the dual-band dual-polarization stacked patch antenna array are shown. The antenna array can operate at 26.5-29.5 GHz and 36.5-44.5 GHz, and the isolation between ports is better than 10 dB.

[0032] Figure 7 (a) ~ (c) is a diagram of the present invention. Figure 3The beam scanning angle results of the dual-band dual-polarization stacked patch antenna array at 28 GHz, 39 GHz and 43.5 GHz are shown, and the 3 dB scanning angles are -53°~54°, -45°~60° and -44°~60° respectively.

[0033] The above-described embodiments merely express the implementation methods of the present invention, but they cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A millimeter wave dual-frequency dual-polarization laminated patch antenna array, characterized in that: The antenna array is formed by a plurality of millimeter-wave dual-frequency dual-polarization stacked patch antenna units of the same structure arranged at intervals on the surface of a metal floor (3); the millimeter-wave dual-frequency dual-polarization stacked patch antenna unit mainly comprises a low-frequency annular metal patch (1), a high-frequency butterfly-shaped metal patch (2), a metal floor (3), an upper dielectric substrate (4), a lower dielectric substrate (5) and a feeding structure, wherein the feeding structure comprises a +45-degree feeding unit (6) and a -45-degree feeding unit (7); The annular metal patch (1) is located on the upper surface of the upper dielectric substrate (4), the butterfly-shaped metal patch (2) is located on the upper surface of the lower dielectric substrate (5), and the lower dielectric substrate (5) is placed on the metal floor (3); the annular metal patch (1) is a square ring structure, and the butterfly-shaped metal patch (2) is obtained by chamfering the four right angles of the rectangular patch; The four end corners of the butterfly-shaped metal patch (2) correspond to the center positions of the four sides of the square ring structure, and the center points of the upper ring-shaped metal patch (1) and the lower butterfly-shaped metal patch (2) can overlap; the ring-shaped metal patch (1) is used to generate low-frequency resonance, and the operating frequency is adjusted by adjusting the size of the ring-shaped metal patch (1); the butterfly-shaped metal patch (2) is used to generate high-frequency resonance, and the high-frequency operating frequency is adjusted by adjusting the size of its rectangular patch and chamfer; Two through holes are provided at corresponding positions on the metal floor (3), the upper dielectric substrate (4) and the lower dielectric substrate (5), respectively used to pass a +45-degree feed unit (6) and a -45-degree feed unit (7), wherein the diameters of the through holes are respectively larger than the outer diameters of the +45-degree feed unit (6) and the -45-degree feed unit (7); the +45-degree feed unit (6) and the -45-degree feed unit (7) are respectively located at the center positions of two vertically adjacent sides of the square ring structure of the annular metal patch (1) to excite antennas with different polarizations; The annular metal patch (1) (1) and the butterfly metal patch (2) are both fed by capacitive coupling, and the capacitive coupling feeding offsets the extra inductance introduced by the orthogonal coaxial feeding; to achieve capacitive coupling feeding, the annular metal patch (1) and the butterfly metal patch (2) are not in direct contact with the +45-degree feeding unit (6) and the -45-degree feeding unit (7), and a circle with a radius greater than the radius of the feeding probe is dug out at the center point of the feeding probe of the upper annular metal patch (1) and the lower butterfly metal patch (2), and the capacitance value is changed by adjusting the radius of the dug circle to improve the matching of the antenna; External coaxial +45-degree feeding units (6) and -45-degree feeding units (7) perform capacitive feeding on the annular metal patch (1) (1) and the butterfly-shaped metal patch (2), and the radio frequency signal enters the annular metal patch (1) and the butterfly-shaped metal patch (2) through capacitive coupling. The resonant frequency of the annular metal patch (1) is a millimeter wave low frequency, and the surface current is distributed on both sides of the metal ring of the feeding port; the resonant frequency of the butterfly-shaped metal patch (2) is a millimeter wave high frequency, and the surface current is distributed on the rounded edge of the patch and moves periodically; due to the orthogonal polarization, the isolation between the antennas is good.

2. The millimeter wave dual-frequency dual-polarization laminated patch antenna array according to claim 1, characterized in that: The radius of the hollowed-out rounded portion of the annular metal patch (1) is 0.18 to 0.2 mm, and the radius of the hollowed-out rounded portion of the butterfly-shaped metal patch (2) is 0.2 to 0.25 mm.

3. The millimeter wave dual-frequency dual-polarization laminated patch antenna array according to claim 1, characterized in that: The feeding probes of the +45-degree feeding unit (6) and the -45-degree feeding unit (7) penetrate all metal and dielectric layers to achieve common feeding of high and low frequencies, and the radius of the feeding probes is 0.15 mm.

4. The millimeter wave dual-frequency dual-polarization laminated patch antenna array according to claim 1, characterized in that: In the antenna array, each antenna unit is arranged in the same direction, and the distance between the center points of adjacent antenna units is 4 mm.

5. The millimeter wave dual-frequency dual-polarization laminated patch antenna array according to claim 1, characterized in that: The +45-degree feeding unit (6) and the -45-degree feeding unit (7) are coaxial with the through hole in which they are installed, and the distance between the +45-degree feeding unit (6) and the -45-degree feeding unit (7) and the inner wall of the corresponding through hole is 0 to 0.1 mm.

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